Insulated wall structure



May 19, 1970 R. K. HUPFER INSULATED WALL STRUCTURE Filed July 21, 1 967 FIGI Wf A M UKM I Mm W Q INVENTOR. 4

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S R EM a F .N wim H W C K W A 2 m, A N m M My 4 Y B 4 3 a 3 (M 12 3 3 1m 4 in L w 5 2 United States Patent 3,512,323 INSULATED WALL STRUCTURE Ronald K. Hupfer, Evansville, Ind., assignor to Whirlpool Corporation, a corporation of Delaware Filed July 21, 1967, Ser. No. 655,228 Int. Cl. E04]: 1/76; E040 2/26 US. Cl. 52309 6 Claims ABSTRACT OF THE DISCLOSURE An insulating wall structure for use in cabinets such as refrigerator cabinets. The wall structure includes a pair of spaced panels and a body of foamed-in-place insulating plastic between the panels. A sheet of fibrous material extends across the space defined by juxtaposed edges of the spaced panels to define a boundary of the insulating plastic and permits the removable installation of a breaker strip between the panel edges.

This invention relates to insulating wall structures and in particular to foamed-in-place insulating wall structures.

In one improved form of insulating wall structure such as for use in refrigerator and freezer cabinets, a body of insulation material is disposed between spaced panels defining the inner and outer wall surfaces. The insulation material is foamed-in-place as by the method shown in the U8. Letters Pat. No. 3,155,751, issued to Carl R. Morris on Nov. 3, 1964, and owned by the assignee hereof. Thus, as disclosed in the Morris patent, the foam material may comprise a urethane foam wherein the foam is generated by a chemical reaction upon mixture of the several ingredients placed in the space between the Wall panels.

As a result of the chemical reaction, the mixed material foams in the space and rises to completely fill the space. Upon setting in the foamed configuration, a resultant bonded foamed-in-place insulating wall structure results. A problem, however, arises in such a foamingin-place operation in that it is difficult to provide precisely the proper amount of ingredients to fully fill the space with the resultant foamed material. If too little foam material is provided, voids occur thereby decreasing the insulating eificiency of the wall structure, and if too much foam material is provided, excessive pressures are built up within the panels. Thus, it has been found necessary to very accurately control the quantity of the foam forming ingredients. Notwithstanding such accurate control, variations in conditions cause an undesirable amount of over-filled and under-filled cabinet structures to result.

The present invention comprehends an improved structural concept which solves the above discussed vexatious problem in a novel and simple manner. More specifically, the present invention comprehends the provision of means for effectively controlling the foaming action to permit a slight excess amount of ingredients to be used for assuring a complete fill of the wall structure, while yet preventing an excessive foam formation causing an over-pressure, or over-fill condition.

Thus, a principal feature of the present invention is the provision of a new and improved insulating wall structure.

Another feature of the invention is the provision of such a wall structure having new and improved means for controlling the foaming-in-place operation to prevent undesirable under-fill and over-fill conditions.

A further feature of the invention is the provision of such an insulating wall structure having new and improved means for permitting a slight excess of foaming material to be used in the foaming-in-place operation 3,512,323 Patented May 19, 1970 ice while yet effectively precluding an over-fill condition.

Still another feature of the invention is the provision of such an insulating wall structure having new and improved means for denucleating a portion of the foam material thereby to prevent an undesirable over-pressure or over-fill condition.

A yet further feature of the invention is the provision of such an insulating wall structure including spaced apart panels having juxtaposed edges defining an opening, and a body of foamed-in-place insulating plastic between said panels, structure for closing the opening comprising a sheet of fibrous material extending across the opening and having an inner portion confronting the plastic, the fibrous material in the inner portion being coated with denucleated plastic, and means for securing the sheet to the edges.

A further feature of the invention is the provision of such an insulating Wall structure further including a breaker strip and means. for removably securing the breaker strip to the panel edges.

Another feature of the invention is the provision of such an insulating wall structure having an electric heater disposed therein and a removable breaker strip providing selective access to the heater when desired.

A further feature of the invention is the provision of such an insulating wall structure wherein the fibrous sheet material provides a body of insulation adjacent the heater.

A yet further feature of the invention is the provision of such an insulating wall structure wherein the fibrous sheet material is provided with an impervious backing layer.

Another feature of the invention is the provision of such an insulating Wall structure wherein the fibrous sheet material is provided with a metal foil backing layer.

Still another feature of the invention is the provision of such an insulating wall structure wherein pressure sensitive adhesive means are provided for securing the fibrous sheet material to one of the panel edges.

In summary, the invention comprehends an improved insulating Wall structure having new and improved means for closing the opening between the juxtaposed edges of the inner and outer panels of a foamed-in-place cabinet wall structure which provides an improved novel control of the foaming operation to effectively preclude an over-fill condition while yet assuring a fully filled condition.

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a fragmentary exploded transverse sectional view of an insulating wall structure embodying the invention;

FIG. 2 is a fragmentary section of the insulating wall structure; and

FIG. 3 is a fragmentary front elevation thereof.

In the exemplary embodiment of the invention as disclosed in the drawing, an insulating wall structure generally designated 10 is shown to comprise a pair of spaced panels 11 and 12 with a body 13 of foamed-in-place plastic therebetween. As indicated briefly above, the wall structure 10 may comprise cabinet wall structure such as for use in a refrigerator or freezer cabinet. Thus, the wall panel 11 may comprise an inner liner panel and the wall panel 12 may comprise an outer cabinet panel. The foam material may comprise a urethane foam material including as the ingredients thereof a polyester and/or polyether resin, toluene diisocyanate, a blowing agent such as Freon 11, Genetron 11, Isotron 11, or Ucon 11, a catalyst such as trimethylamine or triethylenediamine, a surfactant such as the water soluble silicone derivative X-521 manufactured by the Union Carbide Company. The ingredients may be introduced into the spaces 14 between the panels 11 and 12 by suitable nozzles (not shown). After a period of time such as approximately 40 seconds, the ingredients commence foaming and the foam material rises in the space to effectively completely fill the space and form the desired insulation body 13. In the foaming process, the foam body 13 forms a strong bond with the panels 11 and 12 to cause the wall structure to define an integral unit.

In the illustrated embodiment, the wall structure comprises an upright side wall of such a cabinet. FIG. 2 shows a horizontal selection thereof and, thus, the edge portion 15 of the liner panel 11 comprises the front edge of the panel 11 and the edge portion 16 of the cabinet panel 12 defines the front edge thereof which in cooperation with edge 15 defines a front opening 17.

During the foaming-in-place operation, the panels 11 and 12 may be disposed in vertically spaced relationship with the front edges 15 and 16 disposed uppermost. Thus, the foaming of the plastic causes the plastic to rise in the space 14 upwardly toward the opening 17. As indicated briefly above, it is contemplated that in forming the wall structure 10, a slight excess of the foaming ingredients be provided so that ordinarily an excess amount of foam material 13 would be foamed in the space 14 tending to flow outwardly to the opening 17. Thus, it is assured that the space 14 will be completely filled thereby effectively eliminating voids and providing maximum insulating efficiency in the wall structure. To permit such excess ingredient usage while yet prevent excess foam formation tending to produce excessive pressures in the space 14 or forming of the foam material beyond the desired extent thereof, a foam control means generally designated 18 is provided herein which effectively denucleates a portion of the foam during the foaming process and thus eliminates the excessive pressure, over-fill condition More specifically, the foaming control means 18 comprises a strip of fibrous material 19 having an impervious backing layer 20. Illustratively, the fibrous material may comprise fiber glass and the backing layer 20 may comprise a metal foil layer. In the illustrated embodiment, the fibrous material 19 may have a thickness of approximately one-half inch and the width of the strip, as shown in FIG. 1, may be approximately six inches. As will be brought out in greater detail here following, the control means 18 is'installed within the wall structure 10 to extend across the opening 17 with the fibrous material 19 confronting the foaming space 14. Thus, during the foaming operation, the urethane foam engaging the inner portion 21 of the fibrous material 19 becomes denucleated thereby tending to form a coating of gas-free material on the fibers and releasing the foaming gas therefrom. The amount of foam material which is so denucleated corresponds to the excess foam material formed by the slight excess supply of the foaming ingredients so that the foam body 13 may have normal low density, high insulation characteristics. Should the amount of excess ingredients be sufiicient to cause the denucleated material to extend fully through the fibrous material, the impervious metal foil 20 prevents the flow of the material outwardly through the opening 17. Thus, the foam control means 18 effectively defines a barrier at the end of the foaming space 14 which not only delimits the configuration of the foam body 13, but also provides a novel denucleating effect providing control of the foaming operation.

Referring now more specifically to FIG. 1, the edge portion 15 of the liner panel 11 may comprise a turned end portion extending substantially at a right angle to the fiat plate of the panel -11 toward the panel 12 and terminating in a return distal portion 22. As shown, the panel 12 extends forwardly beyond the edge 15 of the panel 11 whereby the edge portion 16 is disposed substantially forwardly of the edge portion 15 of the panel 11. The edge portion 16, as shown in FIG. 1, includes an inturned portion 23, a portion 24 folded back on portion 23, a returned portion 25, an inturned portion 26 and a distal returned portion 27. The panel portions 24, 25 and 26 define a channel space 28 opening away from the fiat plane of the panel 12. The opening 17 from space 14, thusly, is defined by the distal portions 22 and 27 of the panels 11 and 12, respectively.

The foam control means 18 is installed across the opening 17 by means of an adhesive strip 29 extending along one edge of the backing layer 20 for adhesively securing the edge of the control means 18 to the inner surface of the panel 11 at an offset portion 30 thereof spaced slightly from edge portion 15. The opposite edge of the foam control means 18 is folded back upon itself, as shown in FIG. 2, to define a folded portion 31 received in the space 28 of the panel 12.

The wall structure 10 may further include a breaker strip generally designated 32 including a bifurcated end portion 33 resiliently embracing the edge portion 15 of the panel 11, and an opposite inturned latch portion 34 slidably engaging the folded panel portion 24 to removably overlie the foam control means 18. The latch portion 34 is removably retained in the space 28 by means of a spring clip member 35 having an inner wall portion 36 bottomed in space 28 against the return panel portion 25 and having prongs 37 and 38 at the opposite ends thereof for bitingly engaging the panel portions 26 and 24, respectively, to retain the clip member in the space 28. The clip member further includes a spring leg 39 extending along the folded panel portion 24 and having a latch portion 40 at the distal end thereof interlocking releasably with the latch portion 34 of the breaker strip. As shown in FIG. 1, the breaker strip may be further provided with an inturned rib 41 which compresses the foam control means 18 against the distal portion 27 of the panel 12 to provide an effective seal of the foam control means 18 to the panel edge portion 27 and thereby in cooperation with the adhesive securing means 29 securing the foam control means 18 to the panel portion 30, causes the foam control means 18 to define an effective barrier between the panels 11 and 12 inwardly of the opening 17.

A heater wire 42 may be provided in the space 28 adjacent bottom portion 36 of the clip 35 for suitable electrical energization to prevent condensation on the wall edge portions. A strip 43 of masking tape may be provided on the clip member wall 36. As shown in FIG. 2, the folded end portion 31 of the foam control means 18 provides electrical insulation adjacent the heater wire 42, with the metal foil 20 being disposed within the folded portion 31 to be spaced substantially from the heater 42.

Thus, the foam control means 18 effectively precludes bonding of the foam material 13 to the breaker strip and permits the breaker strip to be readily installed and re moved relative to the wall structure 10. Ready access may, therefore, be had to the electric heater wire 42 by simple removal of the breaker strip 32 which may be fabricated from any suitable well-known low heat conducting plastic material. After removal of thermal breaker strip 32 the folded end portion 31 of the foam control means 18 is withdrawn from the space 28 affording ready access to refrigerator electrical wiring such as the heater wire 42. Since the fibrous material 19 is formed of a non-flammable material, such as fiber glass, the folded portion 31 effectively defines a fire barrier providing improved safety in the wall structure.

Thus, the illustrated foam control means 18 effectively defines a barrier in the end of the foam space 14 wherein the fibers of the fibrous material in the inner portion of the foam control means are permeated by the foam material such that the fibrous material is in intimate contact with the foam body 13, and impervious foil backing layer 20 ensures easy removal of breaker strip 32 without destroying the breaker strip or disturbing the insulation. The present invention also permits easy access to refrigerator wiring such as heater wiring and provides an effective fire barrier around the heater wire as required by industry standards such as those of Underwriters Laboratories. The present invention also facilitates easy removal and replacement of breaker strips which are easily broken since they are commonly fabricated from relatively fragile matetrial.

While I have shown and described one embodiment of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:

1. In an insulating wall including spaced apart panels having juxtaposed edges defining an opening, and a body of foamed-in-place insulating plastic between said panels, structure for closing said opening comprising means for denucleating foamed plastic at said opening at the end of the foaming-in-place operation to prevent build-up of excessive pressure by an excess of plastic forming materials in the space between said panels, said denucleating means comprising a fibrous material sheet provided with an outer portion of material impervious to the foamed-inplace plastic and having an inner portion coated with denucleated plastic.

2. In an insulating wall including spaced apart panels having juxtaposed edges defining an opening, and a body of foamed-in-place insulating plastic between said panels, structure for closing said opening comprising: a sheet of fibrous material extending across the opening and having an inner portion confronting the plastic, the fibrous material in said inner portion being in intimate contact with the plastic; and means for securing the sheet to said panels, said sheet being provided with an outer metal foil layer.

3. In an insulating wall including spaced apart panels having juxtaposed edges defining an opening, and a body of foamed-in-place insulating plastic between said panels, structure for closing said opening comprising: a sheet of fibrous material extending across the opening and having an inner portion confronting the plastic, the fibrous material in said inner portion being in intimate contact with the plastic; and measn for securing the sheet to said panels, said securing means including adhesive mean for ecuring the sheet to one of said panels.

4. In an insulating wall including spaced apart panels having juxtaponsed edges defining an opening, and a body of foamed-in-place insulating plastic between said panels, structure for closing said opening comprising: a sheet of fibrous material extending across the opening and having an inner portion confronting the plastic, the fiborus material in said inner portion being in intimate contact with the plastic; and means for securing the sheet to said panels; a breaker strip outwardly overlying said sheet; and means for removably securing said breaker strip to said panel edges, said securing means including a clip member secured to one of said panel edges and having a spring portion resiliently releasably engaging said breaker strip, said fibrous material sheet engaging said clip member.

5. In an insulating wall including spaced apart panels having juxtaposed edges defining an opeing, and a body of foamed-in-place insulating plastic between said panels, structure for closing said opening comprising: a sheet of fibrous material extending across the opening and having an inner portion confronting the plastic, the fibrous material in said inner portion being in intimate contact with the plastic; and means for securing the sheet to said panels, said fibrous material sheet including an edge portion folded back upon itelf and one of said panel edges defining a channel snugly receiving said sheet edge portion.

6. In an insulating wall including spaced apart panels having juxtaposetd edges defining an opening, and a body of foamed-in-place insulating plastic between said panels, structure for closing said opening comprising: a sheet of fibrous material extending across the opening and having an inner portion confronting the plastic, the fibrous material in said inner portion being in intimate contact with the plastic; and means for securig the sheet to said panels, said securing means comprising a pressure adhesive strip on said fibrous material sheet.

References Cited UNITED STATES PATENTS 3,155,751 11/1964 Morris 264-45 3,209,056 9/1965 Jacobs 264-45 X 3,288,894 11/1966 Deaton 26445 X PRICE C. FAW, IR., Primary Examiner US. Cl. X.R. 

